Fiber optic tube assemblies and cables include optical waveguides such as optical fibers that transmit optical signals such as voice, video, and/or data information. Depicted in FIG. 1 is a conventional fiber optic tube assembly 10. Conventional tube assembly 10 includes a plurality optical waveguides 12 in a ribbon format that are disposed within a tube 15 filled with a thixotropic material 14 such as grease. Filling tube 15 with thixotropic material 14 serves several functions. For instance, thixotropic material 14 allows for movement between the optical waveguides and the tube, cushioning of the optical waveguides, coupling of the optical waveguides with the tube, and blocking the migration of water within the tube. Additionally, injecting thixotropic material 14 inside tube 15 during the extrusion of tube 15 around optical waveguides 12 aids in maintaining the shape of tube 15. In other words, injecting thixotropic material 14 to fill tube 15 helps tube 15 maintain its desired shape before the tube 15 is cooled. Without injecting thixotropic material 14, the tube would tend to deform before cooling.
On the other hand, thixotropic materials have drawbacks. One such drawback is that they must be cleaned from the optical waveguide before connectorization of the same. Cleaning the thixotropic material from the optical waveguide is a messy and time-consuming process. Moreover, the viscosity of thixotropic materials is generally temperature dependent. Due to changing viscosity, the thixotropic materials can drip from an end of the tube at relatively high temperatures or the thixotropic materials may cause optical attenuation at relatively low temperatures. Thus, cable designs have attempted to eliminate thixotropic materials from the tube, but it has been a difficult task because the thixotropic material performs many functions. One design that eliminates the thixotropic material from the tube is U.S. Pat. No. 4,909,592, which discloses a tube having water-swellable tapes and/or yarns disposed therein. This design requires a large number of water-swellable components within the tube, which makes the design relatively expensive. Additionally, with the elimination of the thixotropic material the tube is likely to deform or collapse before cooling. This deformation of the tube is not addressed by the patent and can cause numerous problems. Problems caused by tube deformation include increased optical attenuation, decreased tube crush strength, kinking of the tube, non-uniform jacket thickness over the tube, larger cable diameters, and difficulties in stranding the tube about a central member.